This invention relates a piping branch structure, and, more particularly to a piping branch structure in recirculation system of a reactor or the like.
When a boiling water reactor (BWR) plant is operating, cooling water flows through a piping of recirculating system so that the water in a pressure vessel can recirculate therethrough.
For this purpose, in, for example, Japanese Laid Open Application No. 80095180, a cross branch pipe is used in the piping.
An object of the present invention is to provide a piping branch structure wherein a fluid flow in the branch section can be stably maintained.
Another object of the present invention is to provide a piping branch structure wherein an occurrance of vortice in the fluid flow can be suppressed.
Another object of the present invention is to provide a piping branch structure wherein a non-vortex flow state can be maintained.
Another object of the present invention is to provide a piping branch structure wherein pressure losses in the each directions of flows can be maintained at a constant level and fluctuations in quantities of distributed flows can be eliminated.
In accordance with the present invention, a piping branch structure is proposed which comprises a branch pipe distributing an inflowing fluid to pipes in at least three directions, and one of said pipes facing a direction of flow of said fluid, wherein a fluid inlet of said one of pipes is protruded into said branch pipe.
In order to suppress the occurrence of a rotational flow of prior art construction, it is sufficient to prevent the generation of either one of these two vortices, so that the generation of the other vortex can be prevented thereby. By protruding a fluid inlet of a pipe which faces a direction of flow of the fluid into the branch pipe, the protruding pipe acts as obstacles, thus no vortex is generated and the non-vortex flow state can be maintain.
Also in the present invention, a length of fluid inlet of the protruding pipe is set such that an upstream end thereof passes an extension line of an inner plane on a downstream side of fluid outlets of said branch pipe which opens in directions different from that of said protruding pipe.
As a result, the flow of fluid is maintained in a single non-vortex flow state and is maintained in the non-vortex state with a small pressure loss coefficient, and thus the flow is always stable.
The present invention has the effect of suppressing the generation of vortex flow, maintaining stably flows in branch sections in a single flow state, and also maintaining stably the flow state in branch flow channels, by a construction in which a pipe receiving a separate flow in the branch pipe section protrudes toward the inside of the branch channel.